Field of the Invention
The disclosure generally relates to a MIMO (Multi-Input Multi-Output) antenna, and more particularly, relates to a MIMO antenna with an EBG (Electromagnetic Band-Gap) structure.
Description of the Related Art
As people demand more and more transmission of digital data, relative communication standards are supporting higher and higher data transmission rates. For example, IEEE 802.11n can support MIMO technology to increase transmission rates. The relative communication standards, such as LTE (Long Term Evolution) and IEEE 802.11ad, also support MIMO operations. As a matter of fact, it is a future trend to use multiple antennas in a mobile device. However, since multiple antennas are disposed in a limited space of a mobile device, the isolation between these antennas should be taken into consideration by a designer.
Traditionally, the method for improving isolation and for reducing mutual coupling between MIMO antennas is to dispose an isolation element between two adjacent antennas, wherein the resonant frequency of the isolation element is approximately equal to that of the antennas such that the mutual coupling between the antennas is rejected. The drawback of the method is low antenna efficiency and bad radiation performance.